The era of robots wandering inside a human body for medical treatments is about to face our generation. Though the research is still in the process of developing magnetic fields and improving robots, the actual application of the medical robots is expected to occur in a decade. In his research “Magnetic Navigation System Utilizing Resonant Effect to Enhance Magnetic Field Applied to Magnetic Robots,” professor Jang Gun-hee of the Department of Mechanical Engineering proposes the improvement of the magnetic navigation system (MNS) via RLC (stands for resistor, inductor, and capacitor) circuit in the hope of its medical application.

Generation of strong magnetic fields in high frequency

When doctors treat for blood vessels related illness like coronary artery diseases or have to execute endoscopic surgeries, they often use catheters (thin tube made from medical grade materials) controlled by their hands and medical, empirical sensations. However, these catheters don’t have the sufficient controllability for the physicians due to their long, flexible wires. “The main point of this research was to minimize the surgical errors that these catheters may incur. So, we decided to make magnetic robots that are microscopic enough to wander inside our vessels,” said Jang.

The types of robots currently in technical development are various- fish type robots, wobby-like robots, swimming robots, helical robots, and more. However, the magnetic robots especially intrigue the academia. “Compressed springs inside the robot will spread out, enhancing its drilling capability inside the vessels, which its movements will be guided by the magnetic system. Improvements in this MNS are significantly vital, as every mechanical motion of the magnetic robots is proportional to the external magnetic field,” emphasized Jang.

Jang has been working on the magnetic navigation system research for about 12 years, which currently resulted in the torque magnetic field on the right.

Through the experiments to unclog the blocked area of tubular environments, Jang and his students researched on a novel MNS with the resonant effect of the RLC circuit. “Simply saying, these robots with the MNS have magnets. When the north pole of the magnet approaches another north pole, it will push, and vice versa in the case of the south pole. This is the simplistic picture of how the magnetic robots and the MNS are working,” said Jang.

Advancement to this fundamental phenomenon, Jang refers to the "closed right hand rule" (Ampere Law that relates the net magnetic field along a closed loop to the electric current passing through the loop) to explain his research. “In our newly developed MNS, inside the diameter of 50 centimeters wide spherical environment, we can create and control strong magnetic field in any direction which eventually generates useful various mechanical motions of the magnetic robots,” highlighted Jang.

Another unconventional discovery of Jang’s research is the application of resonant frequency in the RLC circuit to amplify the magnetic field of the robot. RLC stands for resistance, inductance, and capacitance which all are in the influential relationships in science. When the alternating voltage is increased, the resistance should be divided to flow the current. However, as the alternating frequency of voltage increases, the current decreases due to the inductance of the coil. “We eliminate the effect of inductance with the application of varying capacitance that leads to maximizing the current and the magnetic field in high frequency,” explained Jang. This phenomenon was able to generate fast drilling motion of the magnetic robot to unclog the blocked area of blood vessels. Furthermore, application of the MNS developed a crawling robot that can also deliver drugs into a human body, which Hanyang University gained its international patent of.

(Video courtesy of Jang)

Hopes for the scientific improvement

It has been a decade since Jang has been working on this magnetic robot research. The beginning of all dates back to when his mother was hospitalized due to her coronary artery disease in the heart. “The doctor told me that the illness is genetic and I may also be in danger. So, I thought that rather than believing in the doctor’s hand and the catheter, I should believe in science to develop this surgical methodology and first test on me,” said Jang.

During the several years that Jang has been working with his students, he also began to long for fostering his students and their success. “I was always interested in the concept of a motor since I was young. This academic desire eventually led me to become a scholar, but since I became a professor of many students and a father of two daughters, I began to be intrigued to their life-long academic achievements,” reminisced Jang.

Ph.D students of the Department of Mechanical Engineering- Lee Won-seo (left) and Nam Jae-kwang (right), also participated in the research with their professor Jang.

It is estimated that after more technical amendments of this mechanical robot, it will be capable of testing on animals, and then applied to human surgeries, which will take about a decade. During this journey to scientific achievements, Jang realized that efforts are what science really value. “Just like my students who endeavored all their desires to science to leap higher, I hope that the South Korean scientific academia will also hope for the brighter future,” reminded Jang.